Movies about wayward kids are a European specialty. The new film “Sister” deepens the specialty. It’s delicately made, yet forceful in its delicacy. The writer and director Ursula Meier takes nothing special — or at least something extremely familiar (a child, left to fend for himself) — and quietly fills it with emotional meaning until you burst with tears. It took the final, breathtaking shot to realize the movie meant as much to me as it did. That’s not filmmaking. It’s sorcery.

Simon (Kacey Mottet Klein) is 12, and spends his mornings and afternoons at a ski resort in the Swiss Alps, picking goodies from unattended backpacks. He resells the top-of-the-line skis he’s stolen and buried in the snow. He makes a regular client of a Scotsman (Martin Compston) who does prep in the kitchen. He makes his way into the locker room of the other men who work at the resort and hawks sunglasses and goggles and helmets. He’s clever and savvy but vulnerable both to the limits of his youth and obvious matters of ethics. When one worker walks off with an item from Simon’s table, he basically says, Hey you didn’t pay for that, and the man says, not unthreateningly,
Neither did you.

With Simon, you know the good days. Those are when he can attempt to buy lunch for one stunningly beautiful, stunningly warm resorter (Gillian Anderson) and two of her children, when he can enjoy a sandwich at a little outdoor table at a lounge, when a stranger can join him at the table and Simon can ask, in his ritziest, most advertorial English, “Can you feel the magic of Prada?”

At least, I think he said “Prada.” He asks with his mouth full. In any case, when the stranger asks him to watch his things, it’s clear Simon’s fooled someone else into assuming he’s on the level. But Simon is actually many levels below. Meier provides more than one arresting shot of the modest tower he lives in with Louise (Léa Seydoux), his older sister. The building sits at the base of the mountains, like a dog waiting to be let in from the cold.

He and Louise share a small unit, and her need for carnal companionship implies that they often have to make room for a third (one fellow with a BMW lasts for a spell). These scenes begin in a rather unimportant way. You understand that Simon wins the bread, and Louise, who looks somewhere between 17 and 24 (Seydoux is 27), obligingly spends it on dates. There are no other adults in their lives. But Simon appears to relish his role as Louise’s provider, as the husband and the daddy. Still, there’s a casual direness in the way he looks at her that’s alarming because it’s not purely sexual. It’s more searching than that. Louise can bear it, and yet she doesn’t seem to understand what more he wants from her — or she refuses to acknowledge it.

Sister

★★★½

MPAA rating:

Unrated

MPAA rating reasons:

(Some language and physical altercations, involving a child and an adult)

Language:

n French, with English subtitles

Running time:

97 minutes

Cast:

Kacey Mottet Klein, Léa Seydoux, Martin Compston, Gillian Anderson

Director:

Ursula Meier

Writers:

Ursula Meier

Playing at:

Kendall Square

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A movie about one child turns into a movie about two children, and how they’ve wound up with their roles reversed. He sends her off to do his grifting after things at the resort get too hot for him. But eventually his envy of the men in her life burns him up, and he says something aloud that stops the movie you assumed you were watching in its tracks. The meaning of subsequent moments — and many that preceded them — doubles. Suddenly, the emotional stakes — and the climactic mud-wrestle between them — seem higher, more loaded.

Meier’s previous movies — “Home” (2008) and “Strong Shoulders” (2003) — are also works of finely etched minimalism. Here, she doesn’t overdo a thing. Her scope is narrow so that the small coincidences in her script, like one involving Anderson’s ethereal reappearance, feel manageable, plausible, and necessary dramatically. The movie’s realism curves outward into melodrama, the classical kind that relies on the power of imagery, symbolism, and circumstance to wreck you. You need to understand what all Simon’s hopeful searching is about, what’s provoked Louise’s selfishness, where on earth the grown-ups are. Meier has an answer that’s determined to see past the basic tragedy of Simon and Louise’s lives. It’s sudden and stirring: They’ll be each other’s grown-ups.